Metamaterial adhesives for programmable adhesion through reverse crack propagation

Hwang, Dohgyu; Lee, Chanhong; Yang, Xingwei; Perez‐González, José; Finnegan, Jason; Lee, Bernard T.; Markvicka, Eric J.; Long, Rong

doi:10.1038/s41563-023-01577-2

Cited by 43 publications

(16 citation statements)

References 48 publications

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“…[43] In double-sided peeling, the peeling and separation angles are not the same (the separation angle is significantly smaller). Detaching the top layer with double-sided peeling mechanics requires a significantly higher pulling force compared to single-sided peeling, due to the smaller separation angle (the same concept has been employed to increase the peeling threshold of adhesive tapes by an order of magnitude in metamaterial adhesives [45] ). In the desired working condition for a PopTouch button, the peeling threshold for Anchored-HAXELs is estimated to be 3.9 N (details are given in Section S1.3, Supporting Information).…”

Section: Anchored-haxels For Actuating Poptouchmentioning

confidence: 99%

“…To effectively increase the peeling threshold, the length and width of the anchors (l anchor and w anchor in Figure 2d) must be larger than a characteristic length. [45] For Anchored-HAXELs, we estimated this characteristic length to be 0.2 mm (details in Section S1.3, Supporting Information). Above this value, further increasing the length of the anchor does not increase the peeling threshold (and in turn the snap-through threshold) of the actuator (details of a parametric study for anchor's length in Section S2.2, Supporting Information).…”

Section: Anchored-haxels For Actuating Poptouchmentioning

confidence: 99%

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PopTouch: A Submillimeter Thick Dynamically Reconfigured Haptic Interface with Pressable Buttons

Firouzeh,

Mizutani,

Groten

et al. 2023

Advanced Materials

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Our interactions with touchscreens rely heavily on vision: we press virtual buttons and push virtual sliders that provide no mechanical sense of the object they seek to represent. We report here PopTouch: a 500 μm thick flexible haptic display that creates pressable physical buttons on demand. PopTouch can be mounted directly on touchscreens or any other smooth surface, flat or curved. The buttons of PopTouch are independently controlled hydraulically amplified electrostatic zipping taxels (tactile pixels) that generate 1.5 mm of out of plane displacement. When pressed by the user, the buttons provide intuitive mechanical feedback thanks to a snap‐through characteristic in their force‐displacement profile. The snap‐through threshold can be as high as 4 N, and is tuned by design and actuation parameters. We present two versions of PopTouch: a transparent PopTouch for integration on Touchscreens with built‐in touch sensing, such as smartphones and a sensorized PopTouch, with embedded thin‐film piezoelectric sensors on each taxel, for integration on substrates without built‐in touch sensing, such as a steering wheel. PopTouch adds static and vibrating button‐like haptics to any device thanks to its thin profile, flexibility, low power consumption (6 mW per button), rapid refresh rate (2 Hz), and freely configured array format.This article is protected by copyright. All rights reserved

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Section: Anchored-haxels For Actuating Poptouchmentioning

confidence: 99%

Section: Anchored-haxels For Actuating Poptouchmentioning

confidence: 99%

PopTouch: A Submillimeter Thick Dynamically Reconfigured Haptic Interface with Pressable Buttons

Firouzeh,

Mizutani,

Groten

et al. 2023

Advanced Materials

View full text Add to dashboard Cite

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“…Apart from the effect of the polymer matrix of peelable coatings on the tunable adhesion and cohesion, the performance (i.e., type, content, or structure) of the microwave absorber also affects the trade-off in adhesion and cohesion . The presence of microwave absorber can increase the cohesive strength and stiffness of coatings, which are associated with the control of adhesion. , The filler contents will inevitably affect the structural integrality and energy dissipation under the external force of the coating, − which is vital for the desirable peelability. Therefore, in view of the complex and diverse chemical/physical bonds and surface-interface interactions between the microwave absorber and polymer matrix of coating, developing a simple and novel peelable MA coating system is highly desired.…”

Section: Introductionmentioning

confidence: 99%

Peelable Microwave Absorption Coating with Reusable and Anticorrosion Merits

Li,

Shi,

Zhang

et al. 2024

ACS Appl. Mater. Interfaces

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The peelable microwave absorption (MA) coating with reversible adhesion for stable presence on substrates and easy release without any residuals is highly desired in temporary electromagnetic protection, which can quickly enter and disengage the electromagnetic protection state according to the real-time changeable harsh surroundings. On the contrary, with the incorporation of abundant absorbent to achieve excellent MA ability, the tunable adhesion and sufficient cohesion are extremely challenging to fulfill the above requirement. The reported peelable coatings still have problems in controlling adhesion/cohesion strength and coating release, facing substantial residuals after peeling even using complex chemical modification or abundant additives. Herein, a peelable MA coating based on the block characteristics of polar and nonpolar segments of poly(styrene-(ethylene-co-butylene)-styrene) (SEBS) is successfully developed. The polyaniline-decorated carbon nanotube as a microwave absorber plays a positive influence on the adhesion/cohesion of the coating due to bonding interaction. The competitive effective absorption bandwidth (EAB) of 8.8 GHz and controllable yet reversible adhesion release on various substrates and complex surfaces have been achieved. The reusability endows peelable MA coating with 93% retention of EAB even after ten coating-peeling cycles. The coating with excellent chemical and adhesion stability can effectively protect substrates from salt/acid/alkali corrosion, showing over 98% retention of EAB even after 8 h of accelerated corrosion. Our peelable MA coating via a general yet reliable approach provides a prospect for temporary electromagnetic protection.

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“…Nature employs many forms of anisotropic adhesion and wetting to realize directionality, such as gecko feet, , lotus flowers, , octopus tentacles, , and butterfly wings . Recent studies have focused on mimicking nature to achieve directional adhesion; however, the methods developed require surface patterning through lithography or laser cutting − or a combination of several different materials, − which complicates processing. Another potential route to anisotropic adhesion is to exploit materials with inherent molecular-scale anisotropy such as liquid crystalline elastomers (LCEs).…”

Section: Introductionmentioning

confidence: 99%

Directional Adhesion of Monodomain Liquid Crystalline Elastomers

Pranda,

Hedegaard,

Kim

et al. 2024

ACS Appl. Mater. Interfaces

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Pressure-sensitive adhesives (PSAs) are widely employed in consumer goods, health care, and commercial industry. Anisotropic adhesion of PSAs is often desirable to enable high force capacity coupled with facile release and has typically been realized through the introduction of complex surface and/or bulk microstructures while also maintaining high surface conformability. Although effective, microstructure fabrication can add cost and complexity to adhesive fabrication. Here, we explore aligned liquid crystalline elastomers (LCEs) as directional adhesives. Aligned LCEs exhibit direction-dependent stiffness, dissipation, and nonlinear deformation under load. By varying the cross-link content, we study how the bulk mechanical properties of LCEs correlate to their peel strength and peel anisotropy. We demonstrate up to a 9-fold difference in peel force measured when the LCE is peeled parallel vs perpendicular to the alignment axis. Opportunities to spatially localize adhesion are presented in a monolithic LCE patterned with different director orientations.

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Metamaterial adhesives for programmable adhesion through reverse crack propagation

Cited by 43 publications

References 48 publications

PopTouch: A Submillimeter Thick Dynamically Reconfigured Haptic Interface with Pressable Buttons

PopTouch: A Submillimeter Thick Dynamically Reconfigured Haptic Interface with Pressable Buttons

Peelable Microwave Absorption Coating with Reusable and Anticorrosion Merits

Directional Adhesion of Monodomain Liquid Crystalline Elastomers

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